The present invention, subject of Disclosure Document No. 299257 which was filed on Jan. 13, 1992, relates to an excavation shoring system for use in excavation depressions such as construction pits and trenches, as well as cuts in sloped earthen banks, to provide worker safety from the hazard of cave in while occupying and working within the excavated depression or cut.
One of the current construction practices in traversing an established roadway with an underground pipe, conduit, cable or the like is to tunnel under the roadway rather than cut, trench, fill and repair thereby preserving the structural integrity of the road bed and surface and not shutting down use of the roadway during construction operations. If the roadway underground crossing site is located on flat terrain then it is necessary to prepare an excavation depression or pit on either side thereof and tunnel underneath. If the roadway is on an elevated earthen bed then tunneling may be accomplished directly therethrough. In either event, however, with the use of power boring and drilling equipment within an excavated depression or within a cut at an earthen slope, and for purposes of general worker safety, it is prudent if not necessary to provide shoring support for the excavation walls or sides of a sloped cut to reduce the danger from cave in.
The prior art shows various shoring systems of modular component assembly, typical of which are those respectively taught in U.S. Pat. No. 4,685,837 to Cicanese dated Aug. 11, 1987, and as shown in the Pit Excavation System brochure of Krings Construction systems of Bridgewater, N.J., both of which have solid side shoring panels and require heavy lifting and rigging equipment to accomplish erection and installation.
An additional feature of the applicant's excavation shoring system invention is that it employs the use of a grid type side shoring panel which itself is suitable for supporting many types of soils, and is adapted to slidably receive planks for providing increased shoring support with less stable soils. The shoring grid feature enables two advantages not realized by the foregoing teachings. First, the overall shoring system is lighter since solid sheet steel side panel members are not used and it can be installed and removed with lighter equipment and second the relatively open grid system to the extent it is not necessary to be planked allows for better visibility into the shored excavation depression when installing and removing men and material and equipment, which is an enhanced safety feature.
A prior art teaching which does show a slotted plank earth shoring system is that by Dorey in U.S. Pat. No. 2,246,623 dated Jun. 24, 1941, for a knockdown cribbing assembly for graves, which is both structurally and functionally distinguished from applicant's teaching, however, in that the shoring planks are not slidably installed only to the height needed and thereby no enhanced visibility feature is achieved.
Applicant's excavation shoring system invention, in both the preferred and alternate embodiment forms thereof, provides in each case individually and interchangeably, new and novel systems and apparatus for the safe and efficient flexibly adaptable shoring of both excavation depressions and sides of cuts in sloped earthen banks to provide worker and equipment protection against cave in.